package com.tamsiree.rxui.view.scaleimage.decoder

import android.content.Context
import android.graphics.Bitmap
import android.graphics.Point
import android.graphics.Rect
import android.net.Uri

/**
 * @author tamsiree
 * Interface for image decoding classes, allowing the default [android.graphics.BitmapRegionDecoder]
 * based on the Skia library to be replaced with a custom class.
 */
interface ImageRegionDecoder {
    /**
     * Initialise the decoder. When possible, initial setup work once in this method. This method
     * must return the dimensions of the image. The URI can be in one of the following formats:
     * File: file:///scard/picture.jpg
     * Asset: file:///android_asset/picture.png
     * Resource: android.resource://com.example.app/drawable/picture
     *
     * @param context Application context. A reference may be held, but must be cleared on recycle.
     * @param uri     URI of the image.
     * @return Dimensions of the image.
     * @throws Exception if initialisation fails.
     */
    @Throws(Exception::class)
    fun init(context: Context?, uri: Uri?): Point?

    /**
     * Decode a region of the image with the given sample size. This method is called off the UI thread so it can safely
     * load the image on the current thread. It is called from an [android.os.AsyncTask] running in a single
     * threaded executor, and while a synchronization lock is held on this object, so will never be called concurrently
     * even if the decoder implementation supports it.
     *
     * @param sRect      Source image rectangle to decode.
     * @param sampleSize Sample size.
     * @return The decoded region. It is safe to return null if decoding fails.
     */
    fun decodeRegion(sRect: Rect?, sampleSize: Int): Bitmap?

    /**
     * Status check. Should return false before initialisation and after recycle.
     *
     * @return true if the decoder is ready to be used.
     */
    val isReady: Boolean

    /**
     * This method will be called when the decoder is no longer required. It should clean up any resources still in use.
     */
    fun recycle()
}